1. Field of the Invention
The invention relates to a control device and control method for an internal combustion engine mounted on a vehicle, or the like, and, more particularly, to a control device and control method for an internal combustion engine that includes a variable valve mechanism that is able to change the operation timing of an intake valve.
2. Description of Related Art
Internal combustion engines mounted on vehicles, or the like, increasingly employ a variable valve timing (VVT) mechanism that allows the operation timing of an intake valve to be variable. For example, Japanese Patent Application Publication No. 2006-214386 (JP 2006-214386 A) describes a configuration that an output shaft of an electric motor is coupled to a camshaft that actuates an intake valve and then an intake-side cam phase is continuously advanced or retarded through control over the rotation speed of the electric motor.
In JP 2006-214386 A, a rotation sensor is provided in the electric motor, and the rotation speed or rotation position of the electric motor is detected by a signal from the rotation sensor. When there occurs a failure in a crank position sensor, so-called fail-safe control is executed. In the fail-safe control, fuel injection, ignition timing, and the like, of the internal combustion engine are controlled by utilizing the signal from the rotation sensor of the electric motor instead of a signal from the crank position sensor (crank signal).